1. Field of the Invention
The present invention relates to an optical component available for use in the field of optical communication, optical signal processing and the like, and particularly to an optical branching device or branch waveguide.
2. Related Background Art
In the fields of optical communication and optical signal processing, waveguide type optical branching devices are often utilized responding to demands for miniaturization of optical components. A representative optical branching device is described in Japanese Patent Application Laid-open No. HEI 5-11130 (11130/1993). Also, directional coupler is described in Journal of Lightwave Technology 10(2): 1843-1849, December 1992.